Today was another good day of arm locking. 

The comm handoff was still reliable this morning.  I had a look at the open loop gain, and decided to try using higher gain. I was able to push the loop gain up to 35kHz, where we have 40 degrees phase margin.  I turned the PLL gain down to 27dB to move the gain peaking to lower frequencies in order to make the higher ugf stable.  With a CM board gain of 18, I was able to engage the first boost in addition to the common compensation.  Data and plots of the new open loop gain are attached. (59 is a GIF, 58 is phase and 57 is magnitude)

Qualitatively, this makes the IR resonance in the arm more stable.  I've attached a stiptool showing the transmitted IR at the settings we have been using up to now, 9dB, and in the laster part with 18dB and the first boost on.  Maybe there is hope after all for ALS COMM. 

I also lowered the UGF of the IMC VCO frequency servo to 0.7 Hz, since it oscillates sometimes. 

We need to start thinking about how to align the IR to the arm cavity.  Today I tweaked PR2 and IM4 by hand.  The red team is already doing a dither alignment on PR2, it would be nice if we could add the IR transmitted signal to this so we could use it to align to the arm. 

I also had made a twinCAT library a while ago that was intended to automate finding the IR resonance in the arm cavity.  I added an medm screen to the ALS overview screen, but this still needs work.